In the field of dental care, replacement teeth are typically retained in place by means of bridge work or the like extending from the replacement tooth and anchored to adjacent healthy teeth. The manufacture of such replacement teeth and their mechanical bridge structure requires careful work to insure proper fitting thereof with respect to adjacent teeth. Also, restoration procedures such as the capping of decayed or broken teeth likewise requires precise positioning with respect to approximate teeth.
To accurately form and position the replacement tooth or cap, a dentist usually makes a dental go negative or impression of the relevant tooth or gap typically including at least the adjacent teeth. This impression may be partial, unilateral or bilateral, depending upon the extent of the work to be done, and serves as a mold for eventual developing of a die of the patient's tooth to be replaced or restored.
For example, when a tooth is to be crowned or otherwise rebuilt, it is conventional to make a negative, casting or impression of the tooth using a rubber-like impression material. The impression then used as a mold for preparing a positive replica of the tooth to be restored. The replica is then used to assist in forming a crown model of the tooth which in turn provides a form or die for making the crown. If needed, a full-bite positive replica of the teeth will be prepared for use in insuring that the upper and lower teeth sets will be closed together properly.
During preparation of the replica tooth or cap, it is usually necessary to remove the casting of its precusor or mock-up from the complete casting, often several times. To do this, the casting, such as for example, a jaw-shaped positive or replica of the gum and upper or lower teeth set is cut through and a slice of replica gum and teeth set removed from the set. In this regard, in order to provide a template on which to reassemble the pieces of the set, a removable base is typically affixed, such as for example, by casting onto the replica teeth set and gum before it is cut into sections. In order that the individual pieces may be accurately reassembled in the initial mold, and in accordance with heretofore conventional practices, each piece is provided with a locating pin or the like which fits into a hole in the base. The pins are set into the replica pieces during the molding operation.
This technique for preparing the replica such that it can be reassembled in a mold or on a base in proper relation to adjacent teeth in the set requires that the pins be very accurately positioned in the fluid dental stone in which the replica tooth or teeth are to be formed. This procedure is difficult because the mold is filled with the molding material thus obscuring the pins. Further, the outline of the teeth is not visible from the outside of the mold.
One solution to these drawbacks is described in U.S. Pat. No. 5,306,145. This patent describes a molding device having an open-top cavity for containing dental stone material, and a spine removably insertable into the floor of the cavity. While this device overcame many of the heretofore known drawbacks to modeling devices, a need still exists for a modeling device which will allow very precise control over the placement of the tooth model into and out of the cavity repeatedly.
Furthermore, a need also exists for a tray with improved set stone removable capability, without detrimentally effecting the accuracy of the replacement of the stone into the tray. The tray should also be capable of efficiently cooperating with an articulator device.